Update on investigations into Settlement errors at two GSP groups

Elexon has been investigating errors in Settlement related to two Grid Supply Point (GSP) Groups: South Eastern GSP Group (Group _J); and London GSP Group (Group _C). This follows our continued monitoring of the Annual Demand Ratio (ADR).

Performance review for GSP Groups

Maintaining Settlement accuracy is of upmost importance to us, and we continually review performance against the ADR for all 14 GSP Groups.

We took a paper to the BSC Panel on Thursday 12 May to provide them with an update on the issue and allow Panel members to ask questions. 

Site investigations confirmed meter errors

On-site investigations by our Technical Assurance Agent at GSP Groups _J and _C confirmed that (in both cases) the meters had been connected in reverse – meaning they were recording energy coming into the GSP Group as energy being exported from the GSP Group, and vice versa.

Both meters have been fixed and now we need to make sure that any historical Settlement data is corrected.

For GSP Group _C, the correction will take place during the normal Settlement Runs.

However, for the site at GSP Group _J, the issue dates back longer than the usual 14 month timescales for full completion of Settlement.

Therefore Trading Dispute DA1121 was raised to correct data from as far back as 28 months ago, and approved by the Trading Disputes Committee in April.

Estimated impact of around £117.5m

We estimate the total impact of these two errors at around £117.5 million. This was calculated using our Extra Settlement Determination (ESD) tool to essentially replicate the normal Settlement calculations but with the corrected volumes used.

In line with Settlement principles some Parties will receive sums as a result of the reconciliation and others will need to pay, reflecting historic over or under charging based on the previously incorrect data.

Elexon has contacted the most affected Parties

We recognise that the impact of these errors is significant, particularly in the context of current market conditions. Over the past few weeks we have called around 100 of the most impacted Parties to alert them.

Registrants are responsible for meter accuracy

We are reminding Registrants that they must ensure that their meters record accurate and complete data. They must also notify us and other market participants if they notice potential errors. BSC section L, sub-section 2 explains these responsibilities. 

Next steps

As part of our assurance work we have developed a machine learning based model to detect and alert unusual consumption patterns at individual GSP Metering Systems.

We will continue to review the controls on metering and the performance of Registrants and Meter Operators. Where there is evidence of poor performance or non-compliance we will report this to the Performance Assurance Board to consider appropriate actions. 

We will also look at a more detailed review of how Registrants and Meter Operator Agents operate these processes and maintain knowledge within their businesses.

We are also working with National Grid, Central Volume Allocation (CVA) Registrants, CVA Meter Operator Agents and technology provider CGI (which fulfils the Central Data Collection Agent role) to establish better communication channels for reporting and escalating potential errors.


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